Bier Block Anesthesia

- Discussion:
- indicated for fractures of the forearm, wrist, and hand;
- bier block is not appropriate for fractures about the elbow, and may not be appropriate in patients with excessive obesity (w/ a large fatty arm);

- Precautions:
- prior to performing the Bier block, be sure that the tourniquet is working properly;
- if the tourniquet malfunctions and deflates during the case, the patient will likely have a siezure due to lidocaine toxicity;
- in obese patients, consider use of a wide single tournique in order to ensure that there will not be leakage of the lidocaine into the systemic circulation;

- Technique:
- first IV line is place in non injured forearm for administration of sedation and fluids;
- in injured limb, a butterfly needle is placed in a dorsal vein in hand, distal to the fracture site;
- 0.33% lidocaine solution is given in a dose of 0.5 mg/kg;
- 1% lidocaine solution is diluted threefold with normal saline to produce a 0.33% lidocaine solution;
- some authors feel that the addition of fentanyl to the lidocaine adds to patient comfort and extends the patient's tolerance to the tourniquet;
- never use marcaine or any similar long acting anesthetic, since the medication will still be active when the tourniquet is deflated at the end of the case (causing a seizure);
- double pneumatic touriquet is placed on arm; (see tourniquets)
- arm is exsanguinated either by elevating the extremity for 4 min or by wrapping it carefully iwth an elastic bandage;
- it is essential that the esmarch is applied as tightly as possible inorder to achieve best results;
- in the prospective study by Tham and Lim, the authors assessed a modification to Bier's IV regional anaesthesia which introduced a third temporary distal forearm tourniquet;
- this confined the injected lignocaine to the hand, resulting in a higher local lignocaine concentration;
- subsequent exsanguination of the limb then channels the remaining intravascular lignocaine under the distal cuff of a double tourniquet;
- of the 18 patients, none experienced pain during operation and all tolerated the tourniquet without significant discomfort;
- no other anaesthetic complications were encountered;
- more proximal of the two cuffs is inflated to 250-300 mm Hg;
- lidocaine is injected;
- if tournequet pain develops, the distal tournequet is inflatted & then proximal tournequet is released;
- after 30-45 min, most of the lidocaine has been bound to tissues in forearm, therefored, removing the tourniquet at this time does not release a large dose of lidocaine into the general circulation